Field of the Invention
The present invention relates to systems and methods for drying concrete, and more particularly to a system and method for lowering the internal relative humidity inside of a concrete structure through application of a pressurized gas to drive moisture from the pores inside of such concrete structure.
Background of the Prior Art
Moisture in concrete structures can have significantly negative effects on the structural integrity and longevity of such structures. Alkali Silica Reaction, or “ASR,” causes concrete to swell and crack and loose important mechanical and durability properties. Similarly, Alkali Carbonate Reaction, or “ACR,” involves a similar reaction but with dolomitic rocks. A reaction product, alkali-silica gel, is typically observed in concrete that is affected by ASR.
ASR is a chemical reaction between the alkali hydroxides in the pore solution of the concrete and certain forms of reactive silica minerals occurring in some aggregates. The reaction product, an alkali-silica gel, is hygroscopic, and will absorb water and swell if the concrete is in a moist environment. The swelling of the gel can, under certain circumstances, lead to expansion and cracking of the concrete.
A sufficient supply of moisture is required in order for the gel to swell and to thus cause such negative effects. More particularly, an internal relative humidity inside of the concrete structure of 80% is required to sustain such a negatively moist environment. In existing ASR affected structures, the rate of reaction, and thus the rate of damage accumulation, may be reduced by lowering the internal relative humidity.
Thus, there remains a need in the art for a simple system and method for use in an existing concrete structure that is capable of lowering the relative humidity inside of the concrete structure below 80%, and maintaining the internal relative humidity below 80%, to minimize the opportunity for the gel reaction product to absorb water, swell, and cause damage to the concrete structure.